U.S. patent application number 15/412506 was filed with the patent office on 2017-09-28 for electronic component.
The applicant listed for this patent is Taiyo Yuden Co., Ltd.. Invention is credited to Tsuyoshi OGINO, Koji OTSUKA, Takayuki SEKIGUCHI.
Application Number | 20170278624 15/412506 |
Document ID | / |
Family ID | 59897248 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170278624 |
Kind Code |
A1 |
OGINO; Tsuyoshi ; et
al. |
September 28, 2017 |
ELECTRONIC COMPONENT
Abstract
An electronic component according one embodiment of the
disclosure includes an insulator, an internal conductor, and an
external electrode. The insulator may be formed of a material that
contains resin. The internal conductor is provided inside the
insulator and includes a conductive main body and an outer coating
film that is provided on at least a part of a peripheral surface of
the conductive main body and has a resistivity higher than the
conductive main body. The external electrode is disposed on the
insulator and electrically coupled to the internal conductor.
Inventors: |
OGINO; Tsuyoshi; (Tokyo,
JP) ; SEKIGUCHI; Takayuki; (Tokyo, JP) ;
OTSUKA; Koji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taiyo Yuden Co., Ltd. |
Tokyo |
|
JP |
|
|
Family ID: |
59897248 |
Appl. No.: |
15/412506 |
Filed: |
January 23, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 27/32 20130101;
H01F 17/0013 20130101; H01F 27/28 20130101; H01F 27/292 20130101;
H01F 2017/0026 20130101; H01F 27/022 20130101; H01F 2017/004
20130101 |
International
Class: |
H01F 27/32 20060101
H01F027/32; H01F 27/02 20060101 H01F027/02; H01F 27/28 20060101
H01F027/28 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2016 |
JP |
2016-059394 |
Claims
1. An electronic component, comprising: an insulator formed of a
material that contains resin; an internal conductor including a
conductive main body and an outer coating film and provided inside
the insulator, the outer coating film being provided on at least a
part of a peripheral surface of the conductive main body and having
a resistivity higher than the conductive main body; and an external
electrode provided on the insulator and electrically coupled to the
internal conductor.
2. The electronic component of claim 1, wherein the conductive main
body is made of a metal, and the outer coating film is made of an
oxide of the metal.
3. The electronic component of claim 1, wherein the internal
conductor includes a plurality of pillared conductive members that
extend in one axial direction and a plurality of connecting
conductive members that each couples predetermined two pillared
conductive members among the plurality of pillared conductive
members, and the plurality of pillared conductive members and the
plurality of connecting conductive members form a coil portion
wound around an axis perpendicular to the one axial direction.
4. The electronic component of claim 3, wherein the insulator
includes a first insulating layer that has a bonding surface
perpendicular to the one axial direction and a second insulating
layer bonded to the bonding surface, the plurality of pillared
conductive members each include a first via conductive member that
is provided in the first insulating layer and a second via
conductive member that is provided in the second insulating layer
and bonded to the first via conductive member.
5. The electronic component of claim 4, wherein the internal
conductor further includes a contact disposed between the first via
conductive member and the second via conductive member, and the
contact is formed of a conductive material different from that of
the conductive main body.
6. The electronic component of claim 5, wherein the first and
second via conductive members are made of a metallic material
containing copper, silver or nickel, and the contact is formed of a
metallic material containing titanium or chromium.
7. The electronic component of claim 3, further comprising: a
capacitor element including a first internal electrode layer that
is coupled to one end of the coil portion and a second internal
electrode layer that is coupled to the other end of the coil
portion and faces the first internal electrode layer in the one
axial direction, the capacitor element being disposed between the
coil portion and the external electrode
8. The electronic component of claim 1, wherein the internal
conductor includes a plurality of windings, the plurality of
windings form a coil portion that is wound around one axial
direction.
9. The electronic component of claim 1, wherein the insulator is
formed of a material containing resin and ceramic particles.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims the benefit of
priority from Japanese Patent Application Serial No. 2016-059394
(filed on Mar. 24, 2016), the contents of which are hereby
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to an electronic component
such as a coil.
BACKGROUND
[0003] Many electronic apparatus typically include coil components.
Especially for mobile devices, coil components may have a chip form
and may be surface-mounted on a circuit substrate included in the
mobile devices. As an example of the prior art, Japanese Patent
Application Publication No. 2006-324489 disclosed a chip coil
including a helical conductor that is embedded in a hardened
insulating resin and at least whose one end is coupled to an
external electrode. The helical direction of the conductor is
arranged in parallel with the surface of a substrate on which the
coil is mounted.
[0004] As another example, Japanese Patent Application Publication
No. 2014-232815 disclosed a coil component including a resin
insulator, a coil-shaped internal conductor provided inside the
insulator, and an external electrode electrically coupled to the
internal conductor. The insulator is made in a cuboid shape with
the length L, the width W, and the height H, where L>W.gtoreq.H.
The external electrode includes an conductor provided at each end
of a plane perpendicular to the height H direction of the insulator
as viewed in the length L direction. The internal conductor has a
coil axis that is parallel with the width W direction of the
insulator.
[0005] In the above-mentioned prior arts, insulators and conductors
are alternately layered in the height direction using a
photolithography and/or plating technique in order to obtain the
coil component.
[0006] In recent years, miniaturization of components advances and
so too with conductors and their sectional areas included in the
components. Consequently it is very important to prevent
deterioration of electric characteristics of the conductors while
ensuring insulation between the conductors. Compared to electric
components in which insulators are made of ceramics or the like,
electric components in which insulators are made of resin are more
likely to be affected by environments and especially oxidation of
conductors included therein cannot be ignored as the
miniaturization of the conductors advances.
SUMMARY
[0007] In view of the above, one object of the disclosure is to
provide an electric component in which an insulation property
between conductors can be ensured and deterioration of a conductive
property due to environmental changes can be reduced.
[0008] An electronic component according one embodiment of the
disclosure includes an insulator, an internal conductor, and an
external electrode. The insulator is formed of a material that
contains resin. The internal conductor is provided inside the
insulator and includes a conductive main body and an outer coating
film that is provided on at least a part of a peripheral surface of
the conductive main body and has a resistivity higher than the
conductive main body. The external electrode is disposed on the
insulator and electrically coupled to the internal conductor.
[0009] In the electronic component, the internal conductor includes
a conductive main body and an outer coating film that is provided
on the peripheral surface of the conductive main body and has a
resistivity higher than the conductive main body. The outer coating
film serves as a passivation film that prevents the oxidation of
the conductive main body. In this way, it is possible to secure an
insulation property between conductive members of the internal
conductor and to reduce deterioration of the conductive property
due to environmental changes.
[0010] The conductive main body is typically made of a metal and
the outer coating film is made of an oxide of the metal. With the
outer coating film, it is possible to further prevent oxidation of
the conductive main body caused by environmental changes.
[0011] The internal conductor may include a plurality of pillared
conductive members that extend in one axial direction and a
plurality of connecting conductive members that each couples
predetermined two pillared conductive members among the plurality
of pillared conductive members. The plurality of pillared
conductive members and the plurality of connecting conductive
members form a coil portion wound around an axis perpendicular to
the one axial direction.
[0012] The insulator may include a first insulating layer that has
a bonding surface perpendicular to the one axial direction and a
second insulating layer bonded to the bonding surface, In this
case, the plurality of pillared conductive members each include a
first via conductive member that is provided in the first
insulating layer and a second via conductive member that is
provided in the second insulating layer and bonded to the first via
conductive member.
[0013] The internal conductor may further include a contact
disposed between the first via conductive member and the second via
conductive member. The contact may be formed of a conductive
material different from the conductive main body. In this way, it
is possible to further prevent change in the resistive value of the
pillared conductive members caused by environmental changes.
[0014] The first and second via conductive members and the contact
may be formed of any material. For example, the first and second
via conductive members may be made of a metallic material
containing copper, silver or nickel, and the contact may be formed
of a metallic material containing titanium or chromium.
[0015] The electronic component may further include a capacitor
element disposed between the coil portion and the external
electrode. The capacitor element includes a first internal
electrode layer that is coupled to one end of the coil portion and
a second internal electrode layer that is coupled to the other end
of the coil portion and faces the first internal electrode layer in
the one axial direction. In this way, the electric component that
includes both the coil element and the capacitor element can be
provided.
[0016] The internal conductor includes a plurality of windings, and
in this case, the plurality of windings form a coil portion that is
wound around one axial direction.
[0017] The insulator is formed of a material containing resin and
ceramic particles.
[0018] As described above, according to the aspects of the
disclosure it is possible to ensure an insulation property between
conductors and to reduce deterioration of a conductive property due
to environmental changes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a schematic perspective view of an electronic
component according to an embodiment of the disclosure.
[0020] FIG. 2 is a schematic side view of the electronic
component.
[0021] FIG. 3 is a schematic top view of the electronic
component.
[0022] FIG. 4 is a schematic perspective view of the upside-down
electronic component.
[0023] FIGS. 5A to 5F are schematic top views of an electrode layer
included in the electronic component.
[0024] FIGS. 6A to 6E are schematic sectional views of an element
unit area to illustrate a basic manufacturing flow of the
electronic component.
[0025] FIGS. 7A to 7D are schematic sectional views of an element
unit area to illustrate a basic manufacturing flow of the
electronic component.
[0026] FIGS. 8A to 8D are schematic sectional views of an element
unit area to illustrate a basic manufacturing flow of the
electronic component.
[0027] FIG. 9 is a schematic sectional view of a main part of an
electronic component of a comparative example illustrating an
internal structure of the component.
[0028] FIG. 10 is a schematic sectional view of a main part of an
electronic component of one embodiment of the disclosure
illustrating an internal structure of the component.
[0029] FIGS. 11A and 11B are a schematic sectional views of a main
part of an electronic component of one embodiment of the disclosure
illustrating an internal structure and operation of the electronic
component.
[0030] FIG. 12A is a lateral sectional view of an electronic
component 100 as viewed from the X-axis direction to schematically
illustrate its internal structure.
[0031] FIG. 12B is a lateral sectional view of the electronic
component 100 as viewed from the Y-axis direction to schematically
illustrate its internal structure.
[0032] FIG. 13 is a schematic sectional perspective view of an
electronic component according to a second embodiment of the
disclosure.
[0033] FIG. 14 is a schematic sectional perspective view of an
electronic component according to a third embodiment of the
disclosure.
[0034] FIG. 15 is a schematic sectional perspective view of an
electronic component according to a fourth embodiment of the
disclosure.
[0035] FIG. 16 is a schematic sectional perspective view of an
electronic component according to a fifth embodiment of the
disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Embodiments of the disclosure will be described hereinafter
with reference to the drawings.
First Embodiment
[0037] Basic Structure
[0038] FIG. 1 is a schematic perspective view of an electronic
component according to an embodiment of the disclosure, FIG. 2 is a
schematic side view of the electronic component, and FIG. 3 is a
schematic top view of the electronic component. In these drawings,
the X-axis, Y-axis and Z-axis indicate three axial directions that
are perpendicular to each other.
[0039] An electronic component 100 according to the embodiment may
be configured as a coil component that is surface-mounted on a
substrate. The electronic component 100 may include an insulator,
an internal conductor 20, and an external electrode 30.
[0040] The insulator 10 may include a top surface 101, a bottom
surface 102, a first end surface 103, a second end surface 104, a
first side surface 105, and a second side surface 106. The
insulator 10 is made in a cuboid shape that has the width in the
X-axis direction, the length in the Y-axis direction and the height
in the Z-axis direction. The insulator 10 may have a width of 0.05
to 0.3 mm, a length of 0.1 to 0.6 mm, and a height of 0.05 to 0.5
mm. In this embodiment, the width of the insulator 10 may be about
0.125 mm, the length may be about 0.25 mm, and the height may be
about 0.2 mm.
[0041] The insulator 10 may include a body 11 and an upper portion
12. The body 11 may include the internal conductor 20 thereinside
and form a main part of the insulator 10. The upper portion 12
provides the top surface 101 of the insulator 10. The upper portion
12 may be formed as, for example, a printed layer on which a model
number of the electronic component 100 is printed.
[0042] The body 11 and the upper portion 12 may be formed of an
insulating material that mainly contains resin. The insulating
material for the body 11 may be a resin that is cured by heat,
light, a chemical reaction or the like. Such resins may include,
for example, polyimide, epoxy resin, liquid crystal polymer, and
the like. The upper portion 12 may be formed of the above-mentioned
material, or a resin film or the like.
[0043] The insulator 10 may be formed of a composite material that
includes a filler in the resin. As such a filler, ceramic particles
such as silica, alumina, zirconia or the like may be typically
used. Configuration of the ceramic particles may not be
particularly limited but typically be spherical. Alternatively it
may be an acicular shape, a scale-like shape or the like.
[0044] The internal conductor 20 may be provided inside the
insulator 10. The internal conductor 20 may include a plurality of
pillared conductive members 21 and a plurality of connecting
conductive members 22. The plurality of pillared conductive members
21 and the plurality of connecting conductive members 22 together
form a coil portion 20L.
[0045] The plurality of pillared conductive members 21 may be each
formed in a substantially columnar shape with a central axis
arranged in parallel with the Z-axis direction. The plurality of
pillared conductive members 21 may include two groups of the
conductors that are arranged so as to face to each other in the
substantially Y-axis direction. One of the two conductor groups is
first pillared conductive members 211 and the first pillared
conductive members 211 are arranged in the X-axis direction at a
predetermined interval. The other of the two conductor groups is
second pillared conductive members 212 and the second pillared
conductive members 212 are also arranged in the X-axis direction at
a predetermined interval. The substantially columnar shape herein
may include any prism of which cross section perpendicular to the
axis (in the direction perpendicular to the central axis) is a
circle, an ellipse, or an oval. For example, the substantially
columnar shape may mean any prism whose cross section is an ellipse
or an oval in which the ratio of the major axis to the minor axis
is 3 or smaller.
[0046] The first pillared conductive members 211 and the second
pillared conductive members 212 may be configured to have the same
radius and the same height respectively. In the illustrated
example, the first pillared conductive members 211 and the second
pillared conductive members 212 may include five members each. As
will be described later, the first and second pillared conductive
members 211, 212 may be formed by stacking more than one via
conductive members in the Z-axis direction. Note that the reason
why the pillared members have the substantially same radius is to
prevent increase of resistance and this may be realized by reducing
variation in the dimension of the pillared members as viewed in the
same direction to 10% or smaller. Moreover the reason why the
pillared members have the substantially same height is to secure
stacking accuracy of the layers and this may be realized by
reducing a difference in the height of the pillared members to, for
example, 1 .mu.m or smaller.
[0047] The plurality of connecting conductive members 22 may
include two groups of conductors that are formed in parallel with
the XY plane and arranged so as to face to each other in the Z-axis
direction. One of the two conductor group is first connecting
conductive members 221 that extend along the Y-axis direction and
are arranged in the X-axis direction at a predetermined interval so
as to connect between the first pillared conductive members 211 and
the second pillared conductive members 212 respectively. The other
of the two conductor group is second connecting conductive members
222 that extend at a predetermined angle with the Y-axis direction
and are arranged in the X-axis direction at a predetermined
interval so as to connect between the first pillared conductive
members 211 and the second pillared conductive members 212
respectively. In the illustrated example, the first connecting
conductive members 221 may include five connecting conductive
members and the second connecting conductive members 222 may
include four connecting conductive members.
[0048] Referring aging to FIG. 1, the first connecting conductive
members 221 are each connected with upper ends of a predetermined
pair of the pillared conductive members 211, 212, and the second
connecting conductive members 222 are each connected with lower
ends of a predetermined pair of the pillared conductive members
211, 212. More specifically, the first and second pillared
conductive members 211, 212 and the first and second connecting
conductive members 221, 222 may be each connected to each other so
as to form a rectangular helix in the X-axis direction. In this
manner, provided is the coil portion 20L that has the central axis
(a coil axis) in the X-axis direction and has a rectangular
opening.
[0049] The internal conductor 20 may further include an extended
portion 23, a comb-tooth block portion 24 and the coil portion 20L
may be connected to the external electrode 30 (31, 32).
[0050] The extended portion 23 may include a first extended portion
231 and a second extended portion 232. The first extended portion
231 may be coupled to a lower end of the first pillared conductive
member 211 that forms one end of the coil portion 20L, and the
second extended portion 232 may be coupled to a lower end of the
second pillared conductive member 212 that forms the other end of
the coil portion 20L. The first and second extended portions 231,
232 may be provided in the XY plane in which the second connecting
conductive members 222 are provided and may be arranged in parallel
with the Y-axis direction.
[0051] The comb-tooth block portion 24 may include a first
comb-tooth block 241 and a second comb-tooth block 242 that are
disposed so as to face to each other in the Y-axis direction. The
first and second comb-tooth blocks 241, 242 may each be arranged
such that their comb tooth ends face upward in FIG. 1. A part of
the first and second comb-tooth blocks 241, 242 may be exposed on
the end surfaces 103, 104 and the bottom surface 102 of the
insulator 10. The first and second extended portions 231, 232 may
be coupled to a space between predetermined two adjacent comb teeth
of the first and second comb-tooth block portions 241, 242
respectively. At the bottom of the first and second comb-tooth
block portions 241, 242, conductive layers 301, 302 that are
underlayers of the external electrode 30 may be provided
respectively (see FIG. 2).
[0052] The external electrode 30 may form an external terminal for
surface mounting and may include first and second external
electrodes 31, 32 that face to each other in the Y-axis direction.
The first and second external electrodes 31, 32 may be formed in
designated regions on the outer surface of the insulator 10.
[0053] More specifically, the first and second external electrodes
31, 32 may each include a first portion 30A that covers each end of
the bottom surface of the insulator 10 in the Y-axis direction, and
a second portion 30B that covers the end surfaces 103, 104 of the
insulator 10 over a predetermined height of the end surfaces 103,
104 as illustrated in FIG. 2. The first portions 30A may be
electrically connected to the bottoms of the first and second
comb-tooth block portions 241, 242 through the conductive layers
301, 302 respectively. The second portion 30B may be formed on the
end surfaces 103, 104 of the insulator 10 so as to cover the comb
teeth portions of the first and second comb-tooth block portions
241, 242.
[0054] The pillared conductive members 21, the connecting
conductive members 22, the extended portion 23, the comb-tooth
block portion 24, and the conductive layers 301, 302 may be formed
of a metal such as Cu (copper), Al (aluminum), Ni (nickel) or the
like. In this embodiment, these may be formed of copper or a copper
alloy plated layer. The first and second external electrodes 31, 32
may be formed by, for example, Ni/Sn plating.
[0055] FIG. 4 is a schematic side view of the upside-down
electronic component 100. Referring to FIG. 4, the electronic
component 100 may include a film layer L1 and electrode layers
L2-L6. In the embodiment, the film layer L1 and the electrode
layers L1-L6 may be stacked sequentially in the Z-axis direction
from the top surface 101 to the bottom surface 102. The number of
the layers may not be particularly limited and may be six in this
example.
[0056] The film layer L1 and the electrode layers L2-L6 may include
elements of the insulator 10 and the internal conductor 20. FIGS.
5A-5F are schematic top views of the film layer L1 and the
electrode layers L2-L6 of FIG. 4.
[0057] The film layer L1 may be formed of the upper portion 12 that
serves as the top surface 101 of the insulator 10 (FIG. 5A). The
electrode layer L2 may include an insulating layer 110 (112) that
forms a part of the insulator 10 (the body 11), and the first
pillared conductive members 211 (FIG. 5B). The electrode layer L3
may include the insulating layer 110 (113), and via conductive
members V1 that form a part of the pillared conductive members 211,
212 (FIG. 5C). The electrode layer L4 may include the insulating
layer 110 (114), the via conductive members V1, and via conductive
members V2 that form a part of the comb-tooth block portions 241,
242 (FIG. 5D). The electrode layer L5 may include the insulating
layer 110 (115), the via conductive members V1, V2, the extended
portions 231, 232, and the second connecting conductive members 222
(FIG. 5E). The electrode layer L6 may include the insulating layer
110 (116) and the via conductive members V2 (FIG. 5F).
[0058] The electrode layers L2-L6 may be stacked in the height
direction with bonding surfaces S1-S4 (see FIG. 4) interposed
therebetween. Accordingly, the insulating layers 110 and the via
conductive members V1, V2 have boundaries in the height direction.
The electronic component 100 may be manufactured by a build-up
method in which the electrode layers L2-L6 are sequentially
fabricated and layered in the stated order from the electrode layer
L2.
[0059] Basic Manufacturing Process
[0060] A basic manufacturing process of the electronic component
100 will be now described. A plurality of the electronic components
100 may be simultaneously fabricated on a wafer and may be then
diced into pieces (chips).
[0061] FIGS. 6 to 8 are schematic sectional views of an element
unit area to illustrate a part of the manufacturing process of the
electronic component 100. More specifically, in the manufacturing
process, a resin film 12A (the film layer L1) is adhered to a base
plate S to form the upper portion 12 and the electrode layers L2 to
L6 are sequentially formed thereon. As the base plate S, a silicon,
glass or sapphire substrate may be used. Typically a conductive
pattern that forms the internal conductor 20 may be formed by
electroplating, subsequently the formed conductive pattern may be
covered by an insulating resin material to form the insulating
layer 110. These steps may be repeated.
[0062] FIGS. 6A to 6E and FIGS. 7A to 7D illustrate a manufacturing
process of the electrode layer L3.
[0063] In this process, a seed layer (a feed layer) SL1 for
electroplating may be formed on the surface of the electrode layer
L2 by, for example, sputtering (FIG. 6A). The seed layer SL1 may be
formed of any conductive material, for example, Ti (titanium) or Cr
(chromium). The electrode layer L2 may include the insulating layer
112 and the connecting conductive members 221. The connecting
conductive members 221 may be provided under the insulating layer
112 so as to contact the resin film 12A.
[0064] Subsequently a resist film R1 may be formed on the seed
layer SL1 (FIG. 6B). The resist film R1 may be exposed and
developed to form a resist pattern having openings P1 that face the
via conductive members V13 which form a part of the pillared
conductive members 21 (211, 212) through the seed layer SL1 (FIG.
6C). Subsequently a descum process may be performed to remove
resist residue in the opening P1 (FIG. 6D).
[0065] The base plate S may be then immersed in a Cu plating bath
and an voltage may be applied to the seed layer SL1 to form the
plurality of via conductive members V13 made of a Cu plating layer
within the openings P1 (FIG. 6E). After the resist film R1 and the
seed layer SL1 may be removed (FIG. 7A), the insulating layer 113
that covers the via conductive members V13 may be formed (FIG. 7B).
The insulating layer 113 may be formed by printing or applying a
resin material or applying a resin film on the electrode layer L2
and then hardening the resin. After the resin is hardened, the
surface of the insulating layer 113 may be polished so as to expose
tips of the via conductive members V13 by using a polishing
apparatus such as a chemical mechanical polish machine (CMP
machine), a grinder or the like (FIG. 7C). FIG. 7C illustrates an
example of the polishing process (CMP) of the insulating layer 113
with a revolving polishing pad P. Here, the base plate S may be
placed upside down on a polishing head H that is capable of
spinning. As described above, the electrode layer L3 may be formed
on the electrode layer L2 (FIG. 7D).
[0066] A fabrication method of the insulating layer 112 has not
been described above, but it may be typically formed in the same
manner as the insulating layer 113, more specifically, a resin
material may be printed or applied or a resin film may be applied
and then cured. The cured resin may be then polished by chemical
mechanical polishing (CMP), a grinder or the like.
[0067] In the same manner as described above, the electrode layer
L4 may be formed on the electrode layer L3.
[0068] A plurality of via conductive members (second via conductive
members) that are coupled to the via conductive members V13 (first
via conductive members) may be formed on the insulating layer 113
(a second insulating layer) of the electrode layer L3. More
specifically, a seed layer that covers the surface of the first via
conductive members may be formed on the surface of the second
insulating layer. A resist pattern that has openings at the
position corresponding to the surface of the first via conductive
members may be then formed and the second via conductive members
may be formed by electroplating using the resist pattern as a mask.
A third insulating layer that covers the second via conductive
members may be subsequently formed on the second insulating layer.
The surface of the third insulating layer may be then polished to
expose tips of the second via conductive members.
[0069] In the above-described fabrication process of the second via
conductive members, the via conductive members V2 that form a part
of the comb-tooth block portion 24 (241, 242) may be formed at the
same time (see FIG. 4 and FIG. 5D). In this case, the resist
pattern has openings that correspond to the region where the via
conductive members V2 are formed in addition to the openings that
correspond to the region where the second via conductive members
are formed.
[0070] FIGS. 8A to 8D illustrate a part of the manufacturing
process of the electrode layer L5.
[0071] A seed layer SL3 for electroplating may be firstly formed on
the electrode layer L4, and then a resist pattern (a resist film
R3) that has openings P2, P3 may be sequentially formed on the seed
layer SL3 (FIG. 8A). Subsequently a descum process may be performed
to remove resist residue in the openings P2, P3 (FIG. 8B).
[0072] The electrode layer L4 may include the insulating layer 114
and via conductive members V14, V24. The via conductive members V14
may correspond to the via members (V1) that form a part of the
pillared conductive members 21 (211, 212), and the via conductive
members V24 may correspond to the via members (V2) that correspond
to a part of the comb-tooth block portion 24 (241, 242) (see FIGS.
5C and 5D). The opening P2 may face the via conductive member V14
in the electrode layer L4 with the seed layer SL3 interposed
therebetween, and opening P3 may face the via conductive member V24
in the electrode layer L4 with the seed layer SL3 interposed
therebetween. The openings P2 may be each formed in the shape that
conforms to the corresponding connecting conductive member 222.
[0073] The base plate S may be then immersed in a Cu plating bath
and an voltage may be applied to the seed layer SL3 to form via
conductive members V25 and the connecting conductive members 222
made of a Cu plating layer within the openings P2, P3 (FIG. 8C).
The via conductive members V25 may correspond to the via members
(V2) that form a part of the comb-tooth block portion 24 (241,
242).
[0074] After the resist film R3 and the seed layer SL3 are removed
(FIG. 8D), the insulating layer 115 that covers the via conductive
members V25 and the connecting conductive members 222 may be formed
(FIG. 8D). Although it is not illustrated in the drawings, the
surface of the insulating layer 115 may be polished to expose tips
of the via conductive members V25, the seed layer and the resist
pattern may be subsequently formed, and the electroplating process
may be then performed. By repeating the above-described processes,
the electrode layer L5 illustrated in FIG. 4 and FIG. 5E is
fabricated.
[0075] After the conductive layers 301, 302 are formed on the
comb-tooth block portion 24 (241, 242) exposed on the surface (the
bottom surface 102) of the insulating layer 115, the first and
second external electrodes 31, 32 may be formed.
[0076] Structure In The Embodiment
[0077] In recent years, miniaturization of components advances and
so too with conductors and their sectional areas included in the
components. Consequently it is very important to prevent
deterioration of electric characteristics of the conductors while
ensuring insulation between the conductors. Compared to electric
components in which insulators are made of ceramics or the like,
especially the electric components in which insulators are made of
resin are more likely to be affected by environments and especially
oxidation of conductors included therein cannot be ignored as the
miniaturization of the conductors advances.
[0078] FIG. 9 schematically illustrates a section of a bonding
portion between the two electrode layers stacked on top of each
other. The insulating layer LS1 situated as the lower layer may be
bonded to the insulating layer LS2 situated as the upper layer via
a bonding surface SA. A via conductive member VS1 in the lower
layer may be bonded to a corresponding via conductive member VS2
with a contact CA interposed therebetween. The contact CA may
correspond to the seed layer SL situated between the two via
conductive members VS1, VS2. The both sides of the seed layer SL
may form contact surfaces for the via conductive members VS1,
VS2.
[0079] Here, the via conductive members VS1, VS2 may be formed of
metal such as copper and peripheral surfaces of the conductive
members VS1, VS2 may directly contact the insulating layers LS1,
LS2. The insulating layers LS1, LS2 may be formed of a material
that mainly contains resin. There is a possibility that the via
conductive members VS1, VS2 are oxidized due to effects of a
temperature and humidity of a characteristics evaluation test (a
test in the conditions of high ambient temperature and humidity) or
an actual-use environment. Consequently the conductive
characteristics of the via conductive members VS1, VS2 may be
deteriorated.
[0080] In order to avoid this from happening, in the electronic
component 100 according to the embodiment, the plurality of via
conductive members VS1, VS2 that form the pillared conductive
members 21 may each include a conductive main body Vm and an outer
coating film Vc provided on the peripheral surface of the
conductive main body Vm as illustrated in FIG. 10. The outer
coating film Vc is configured to serve as a passivation film that
prevents the oxidation of the conductive main body Vm.
[0081] The structure of the electronic component 100 according to
the embodiment will be now described in detail.
[0082] As described above, the electronic component 100 according
to the embodiment may include the insulator 10 and the internal
conductor 20. The insulator 10 may be formed of a material that
contains resin. The internal conductor 20 may include the pillared
conductive members 21 (211, 212) and may be provided inside the
insulator 10. The pillared conductive members 21 may each include
the conductive main body Vm and the outer coating film Vc that is
provided on the peripheral surface of the conductive main body Vm
and that has a resistivity higher than the conductive main body
Vm.
[0083] In the embodiment, the outer coating film Vc serves as the
passivation film that prevents oxidation of the conductive main
body Vm, ensures the insulation property between the adjacent
pillared conductive members 21, and prevents deterioration of the
conductive property of the pillared conductive members 21 due to
environmental changes. In short, with the outer coating film Vc, it
is possible to prevent further oxidation of the conductive main
body Vm caused by environmental changes.
[0084] Here, the conductive main body Vm may be formed of metal,
for example, made of copper (a Cu plating layer) in this
embodiment. Whereas the outer coating film Vc may be made of an
oxide of the metal used for the conductive main body Vm. In this
embodiment, the outer coating film Vc may be made of copper
oxide.
[0085] The thickness of the outer coating film Vc is not
particularly limited and may be adequately set in accordance with
the diameter, the outer diameter, the thickness or the like of the
conductive main body Vm. The thickness of the outer coating film Vc
may be typically 5 nm to 5 .mu.m (both inclusive). By setting the
thickness of the outer coating film Vc in the above-mentioned
range, it is possible to stably form the outer coating film Vc with
less defects and consequently it is possible to prevent
short-circuit between the adjacent pillared conductive members
21.
[0086] The outer coating film Vc may be formed of any chemical
compound such as nitrides, carbides, sulfides, oxynitrides or the
like other than oxides of the conductive main body Vm.
Alternatively, the outer coating film Vc may be formed of an oxide
of a metallic material other than the metal that forms the
conductive main body Vm.
[0087] Referring again to FIG. 10, the via conductive member VS1
situated in the lower layer may be electrically coupled to the via
conductive member VS2 in the upper layer through the contact CA. As
described above, the contact CA may correspond to the seed layer SL
situated between the two-adjacent via conductive members VS1, VS2.
The both surfaces of the seed layer SL may form contact surfaces
for the via conductive members VS1, VS2. The thickness of the
contact CA is not particularly limited, for example, 5 nm to 20 nm
(both inclusive). In this embodiment, it may be 10 nm. The via
conductive members VS1, VS2 may be formed of titanium or chromium,
and a film of titanium oxide or chromium oxide may be formed on the
peripheral surface of the conductive members VS1, VS2 that contact
the insulating layers LS1, LS2.
[0088] Moreover, the outer coating film Vc may usually have a
higher hardness than the conductive main body Vm. Therefore
compared to a case where the outer coating film Vc is not provided,
the mechanical strength of the pillared conductive members 21 with
the outer coating film Vc is made higher.
[0089] Referring to FIG. 11A, the contact CA between the via
conductive member VS1 and the via conductive member VS2 may be
disposed at an offset position (a position within the insulating
layer LS1 rather than at the bonding surface SA) in the Z-axis
direction with reference to the bonding surface SA between the
insulating layers LS1, LS2. In this way, it is possible to avoid a
contraction stress (.sigma.1) caused by the hardening process of
the insulating layer LS2 and a heat (.sigma.2) caused by a
difference of the thermal expansion rate between the insulating
layer LS2 and the via conductive member VS2 from concentrating on
the contact CA as illustrated in FIG. 11B. Consequently it is
possible to further enhance the reliability of the internal
conductor 20.
[0090] The outer coating film Vc may be provided not only on the
peripheral surface of the pillared conductive members 21 (211, 212)
but also on a part of the peripheral surfaces of the connecting
conductive members 22 (221, 222). Here, "a part of the peripheral
surface" may refer to all the surfaces excluding the contact
surface (the surface contacting the seed layer) of the connecting
conductive member 22. In this way, it is possible to prevent the
oxidation of the connecting conductive members 22 due to
environmental changes, and effectively prevent deterioration of the
electric conductive property over time.
[0091] FIGS. 12A and 12B are side sectional views schematically
showing the internal structure (the coil portion 20L) of the
electronic component 100 as viewed from the X-axis direction and
the Y-axis direction, respectively. The hatched regions in FIGS.
12A and 12B correspond to the pillared conductive members 21 (211,
212) and the connecting conductive members 22 (221, 222) provided
in the electrode layers L2 to L5, respectively.
[0092] In FIGS. 12A and 12B, regions (surfaces) indicated by a bold
solid line correspond to formation regions of the outer coating
film Vc, and regions (surfaces) indicated by a dashed-dotted line
correspond to formation regions of the seed layer that serve as the
contact surface. By providing the outer coating film Vc on all the
surfaces of the pillared conductive members 21 and the connecting
conductive members 22 where contact the insulator 10 as described
above, it is possible to suppress excessive oxidation of conductors
due to oxygen in the insulator 10 and therefore it is possible to
secure stable electrical characteristics of the internal conductor
20. Although it is not shown in the drawings, a similar outer
coating film Vc may be formed on a surface of a conductor portion
(for example, the comb-tooth block portion 24) other than the coil
portion 20L.
[0093] To fabricate the outer coating film Vc, for example, the
electronic component 100 may be placed in a heating furnace to heat
the component. A heating temperature is not particularly limited,
but may be 100 to 250.degree. C. A heating duration is also not
particularly limited, but may be 1 to 12 hours. The heating may be
carried out for a shorter period when the heating temperature is
high and the heating may be carried out for a longer period when
the heating temperature is low. As an atmosphere used for the
heating, the air may be used or a high temperature and high
humidity environment for a durability test may be used. With the
oxygen inside the insulator 10, the outer coating film made of the
oxide of the metal of the internal conductor 20 can be formed on
the surface of the internal conductor 20 and at the same time
deterioration of the resin of the insulator 10 can be
suppressed.
[0094] The heating temperature may be set higher than a temperature
of the actual use environment. For example, the heating temperature
may be 10 to 30.degree. C. higher than the actual use environment
temperature. When heated at this temperature, it is possible to
suppress change of the internal conductor 20 under the actual use
environment. Moreover, the outer coating film Vc formed as
described above is an oxide of the metallic material of the
conductor so that the internal conductor portion will not be
exposed, and even if the thickness is reduced, there will be no
defect.
[0095] Alternatively, the outer coating film Vc may be formed after
the via conductive members are formed by electroplating and before
the insulating layer is formed. In this case, a thermal oxidation
treatment, a coating process with various insulating materials or
the like may be performed on the via conductive members.
[0096] As described above, in the electronic component 100
according to the embodiment, the outer coating film Vc that has a
higher resistance than the conductive main body is provided on the
peripheral surfaces or the surfaces of the conductive main body Vm
of the pillared conductive members 21 and the connecting conductive
members 22, Therefore insulation characteristics between the
conductors in the insulator 10 can be ensured and degradation of
the conductive characteristics of the internal conductor portion
due to environmental changes can be reduced.
[0097] The inventors of the present disclosure measured a change in
the resistance value of the internal conductor before and after a
high temperature test (150.degree. C., 1000 hours) for a sample of
the electronic component that has the outer coating film Vc and a
sample of the electronic component that does not have the outer
coating film Vc. The measurement results found that the change in
the resistance value of the electronic component that does not have
the outer coating film was 5%, whereas the change in the resistance
value of the electronic component that has the outer coating film
was 1% or less.
[0098] Moreover, according to the embodiment, even if a distance
between adjacent conductive members becomes very small due to
elongation (burr) or the like of the end portion of the via
conductive member, which may occur when the surface of the
insulating layer is ground to expose the via conductive members,
such portions are oxidized during the fabrication process of the
outer coating film Vc. In this way, short-circuit failure between
the conductors due to the burr can be prevented.
[0099] The existence of an oxide film such as the outer covering
film Vc on any surfaces between the conductive members of the
internal conductor may reduce migration. Particularly, in the case
of the coil component, by using copper for the conductive members,
migration can be effectively suppressed. Moreover stable coil
characteristics can be secured, and miniaturization of the internal
conductor can be achieved. For example, when silver is used as the
conductive material since silver is the metal that has a low
specific resistivity like copper, 15 .mu.m of the distance between
conductors is required in the case of silver but the distance can
be reduced to 5 .mu.m for the case of copper.
Second Embodiment
[0100] FIG. 13 is a schematic sectional perspective view of an
electronic component according to a second embodiment of the
disclosure.
[0101] Structures different from the first embodiment will be
hereinafter mainly described. The same reference numerals are given
to the same elements as those of the first embodiment, and the
description thereof will be omitted or simplified.
[0102] The electronic component 200 of this embodiment may include
an insulator 2010 and an internal conductor 2020. The internal
conductor 2020 is configured as a coil component including a coil
portion 200L that are wound around the Z-axis direction. The coil
portion 200L in this embodiment may be a stacked-type coil that
includes a plurality of windings 2021 to 2023 (three in this
example) that are stacked in the Z-axis direction with an
insulating layer interposed therebetween.
[0103] Similarly to the first embodiment, the insulator 2010 may be
formed of a material that mainly contains resin and may include a
plurality of insulating layers LS20 stacked in the Z-axis
direction. The electronic component 200 may be fabricated by
building up the insulating layer LS20 and the windings 2021 to 2023
alternately from the lower layer side (or the upper layer
side).
[0104] Each of the windings 2021 to 2023 may be made of copper,
nickel or silver, and may be formed on the insulating layer LS20
that serves as a base layer by electroplating. The windings 2021 to
2023 that face to each other in the Z-axis direction may be
electrically connected through vias (not shown). One end of the
coil portion 200L may be electrically coupled to one external
electrode E1 and the other end may be electrically coupled to other
external electrode E2.
[0105] Similarly to the first embodiment, the windings 2021 to 2023
may each include the conductive main body Vm, the outer coating
film Vc, and the contact CA. The contact CA may be provided in
regions indicated by a dashed-dotted line in the drawing (the lower
surfaces of the windings 2021 to 2023) and may be formed of a seed
layer for electroplating. The outer coating film Vc may be formed
on the peripheral surfaces (upper surface and side surface) of the
conductive main body Vm that contacts the insulating layer LS20
other than the contact CA. The outer coating film Vc may be made of
an oxide of the metal of the conductive main body Vm.
[0106] For the electronic component 200 of this embodiment
configured as described above, it is possible to obtain the same
advantageous effects as the above-described first embodiment. In
particular, according to the embodiment, since the outer coating
film Vc with a higher resistance than the conductive main body Vm
is interposed between the surfaces of the windings 2021 to 2023
opposed in the stacking direction (the Z-axis direction). Therefore
desired insulation characteristics can be ensured even if the
thickness of the insulating layer LS20 situated between the
windings 2021 to 2023 is reduced In this way, it is possible to
reduce the overall thickness of the electronic component 200.
Third Embodiment
[0107] FIG. 14 is a schematic sectional perspective view of an
electronic component according to a third embodiment of the
disclosure. Structures different from the first embodiment will be
hereinafter mainly described. The same reference numerals are given
to the same elements as those of the first embodiment, and the
description thereof will be omitted or simplified.
[0108] The electronic component 300 of this embodiment may include
an insulator 3010 and an internal conductor 3020. The internal
conductor 3020 is configured as a coil component including a coil
portion 300L that are wound around the Z-axis direction. The coil
portion 300L in this embodiment may be a planar type coil (a
helical coil) that includes a plurality of windings 3021 to 3023
(three in this example) that are arranged concentrically in the
Z-axis direction.
[0109] Similarly to the first embodiment, the insulator 3010 may be
formed of a material that mainly contains resin and may include a
plurality of insulating layers LS30 stacked in the Z-axis
direction. The electronic component 300 may be fabricated by
building up the insulating layer LS30 and the windings 3021 to 3023
alternately from the lower layer side (or the upper layer
side).
[0110] Each of the windings 3021 to 3023 may be made of copper,
nickel or silver, and may be formed on the insulating layer LS20
that serves as a base layer by electroplating. The windings 3021 to
3023 may be interconnected to each other so as to be continuous
around the Z-axis. One end of the coil portion 300L may be
electrically coupled to one external electrode E1 and the other end
may be electrically coupled to other external electrode E2.
[0111] Similarly to the first embodiment, the windings 3021 to 3023
may each include the conductive main body Vm, the outer coating
film Vc, and the contact CA. The contact CA may be provided in
regions indicated by a dashed-dotted line in the drawing (the lower
surfaces of the windings 3021 to 3023) and may be formed of a seed
layer for electroplating. The outer coating film Vc may be formed
on the peripheral surfaces (upper surface and side surface) of the
conductive main body Vm that contacts the insulating layer LS30
other than the contact CA. The outer coating film Vc may be made of
an oxide of a metal used as the conductive main body Vm.
[0112] For the electronic component 300 of this embodiment
configured as described above, it is possible to obtain the same
advantageous effects as the above-described first embodiment. In
particular, according to the embodiment, since the outer coating
film Vc with a higher resistance than the conductive main body Vm
is interposed between the surfaces of the windings 3021 to 2023
that oppose to each other in a direction perpendicular to the
stacking direction (the Z-axis direction). Therefore desired
insulation characteristics can be ensured even if the width of the
insulating layer LS30 situated between the windings 3021 to 3023 is
reduced. In this way, it is possible to realize the miniaturization
of the electronic component 200 and the multiplexing of the
windings (increase of the number of the windings).
Fourth Embodiment
[0113] FIG. 15 is a schematic sectional perspective view of an
electronic component according to a fourth embodiment of the
disclosure. For ease of understanding, a region corresponding to
the internal conductor is indicated by hatching. Structures
different from the first embodiment will be hereinafter mainly
described. The same reference numerals are given to the same
elements as those of the first embodiment, and the description
thereof will be omitted or simplified.
[0114] An electronic component 400 in this embodiment may include
the insulator 10, the internal conductor 20, and the external
electrode 30. Like the first embodiment, the electronic component
400 may include the coil component similarly to the first
embodiment but the internal conductor 20 may include two coil
portions 21L and 22L, which is different from the first
embodiment.
[0115] In the electronic component 400 of the this embodiment, the
two coil portions 21L, 22L may be provided in the insulator 10 and
three external electrodes 331, 332, 333 may be provided on the
bottom surface 102 of the insulator 10. The coil portion 21L may be
coupled between the external electrodes 331 and 333, and the other
coil portion 22L may be coupled between the external electrodes 332
and 333.
[0116] The number of the coil portions is not particularly limited
to two as illustrated but may be three or more. The number of the
external electrodes 30 is also not particularly limited to three as
illustrated but may be adequately changed. According to the fourth
embodiment, more than one coil component may be integrated into a
single component.
Fifth Embodiment
[0117] FIG. 16 is a schematic sectional perspective view of an
electronic component according to a fifth embodiment of the
disclosure. For ease of understanding, a region corresponding to
the internal conductor is indicated by hatching. Structures
different from the fourth embodiment will be hereinafter mainly
described. The same reference numerals are given to the same
elements as those of the second embodiment, and the description
thereof will be omitted or simplified.
[0118] An electronic component 500 in this embodiment may include
the insulator 10, the internal conductor 20, and the external
electrode 30. The internal conductor 20 may include two coil
portions 21L and 22L, which is same as the fourth embodiment, but
the internal conductor 20 may further include two capacitor
elements 21C, 22C, which is different from the fourth
embodiment.
[0119] The capacitor element 21C may be provided between the coil
portion 21L and the bottom surface 102 of the insulator 10, and may
be coupled to the external electrodes 331, 333 in parallel with the
coil portion 21L. The capacitor element 22C may be provided between
the coil portion 22L and the bottom surface 102 of the insulator
10, and may be coupled to the external electrodes 332, 333 in
parallel with the coil portion 22L.
[0120] Each of the capacitor elements 21C and 22C may include a
first internal electrode layer electrically coupled to one ends of
the coil portions 21L and 22L and a second internal electrode layer
electrically coupled to the other ends of the coil portions 21L and
22L. The second internal electrode layer may face the first
internal electrode layer in the Z-axis direction to form
capacitors. The capacitor elements 21C, 22 C may be disposed
between the coil portions 21L, 22L and the external electrodes 331
to 333, thereby forming the LC integrated electronic component
500.
[0121] The invention is not limited to the above described
embodiments and various modification can be made.
[0122] For example, in the embodiments described above, the
insulating layers and the via conductive members are alternately
layered from the top surface side to the bottom surface side to
fabricate the electronic component. Alternatively the insulating
layers and the via conductive members may be alternately layered
from the bottom surface side to the top surface side.
[0123] Furthermore, in the above embodiments, the coil component
and the LC component were described as examples of the electronic
component, but it is also possible to use other components such as
a capacitor component, a resistive component, a multilayer wiring
substrate and the like. The invention is also applicable to other
electronic components that include internal conductors and are
formed by building up on a layer-by-layer basis in the height
direction.
* * * * *